Ruby 19 in steel

[DetroiTug]

Ever wondered what a Selway Fisher Ruby 19 would look like in steel?

I drew this up in steel for a buddy of mine last fall and he built it in his garage over the winter. It's got a real "navy" look to it. He said it is very stable and the Pearl engine and VFT boiler pushes it quite fast. He loves it.




-Ron

[fredrosse]

That is a beauty. I guess you can make a steel hull thin enough for a boat less than 20 feet long, with good corrosion protective coatings.

I got started with boats while working for the Army Corps of Engineers, they dredge all the waterways of the US, our district had 3 oceangoing steamships and over 100 support vessels. At that time 1/4 inch plate was as small as we would go, even for a new 34 foot survey boat. We also had a 120 foot tug, with 10 gauge plate for the hull, I though that was too thin, but the tug had been built during WWll, and was still going in the 1960s.

[DetroiTug]

Yes, as soon as the word "steel" is used regarding small hull construction, many are immediately put off to the notion. 10 ga (.140") thick steel seems a bit light for a 120 foot tug. But if it works, it works.

Bill's Ruby above is 12 ga (.105") from the keel to wale. It is a bit of a bobber on the water as the pics show clearly it's not overly heavy.

The reality is if steel is used properly, the hull can wind up weighing less than a comparable composite hull. Fiberglass isn't light, and neither is marine plywood once it's properly braced/framed and then "glassed in". In the case of aluminum, thicker material is used to match the strength of steel and the end result winds up being closer to same. Iron Chief's hull when finished I had it calculated to around 1300 pounds and that is pretty light for a 22 X 8 foot hull. And it's very strong. Two weeks ago, my son was steering and ran out of the buoys on the Champlain canal by not a very far distance and went over submerged rocks. It clanged and banged and bounced and all I was really concerned about was the prop, when we pulled out at Whitehall, I could not see any evidence of the mishap. Must've ran along the deadwood.

Then too, oftentimes hulls are built and it is found that ballast has to be added to bring it down to the water line - why not just build the needed weight in to the hull?

I'm seriously contemplating another larger steel steamtug and this time I will use heavier hull plating. 11 ga (.125) from the keel up. This is a preliminary CAD doodle, but it's actually enough to build from. 28.5" long by 8 foot. My only concern is how stretching the hull will effect the buoyancy and stability. I will make a presentable drawing in 3D and send it to a marine architect for review.

I really like Iron Chief - but it is a bit tight for overnighting. The new proposed tug will have a head for the womenfolk, central heat and air for dockside or gen power, built in berths, after cabin that follows the sheer with a swayback roof. The engine room would be 11 feet long instead of 6.5 feet as it is now. The foredeck is 6" longer and the rear cockpit is 6" longer, Wheelhouse is unchanged. I know most of the pitfalls of construction and my car is almost done and I need another project. They keep me off the streets and out of trouble



-Ron

[fredrosse]

Looks like you will have another great project going! Have you tried DEFTSHIP software? There is a free version available, and it can tell you all kinds of things about your proposed hull, draw the shell expansion plate drawings, identify non-developable surfaces, if there are any, etc. You can work up hull lines with the program, or import a table of offsets to duplicate an already designed hull.